Burster 8524, Руководство по эксплуатации

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Special techniques are used to mount strain gages manufactured in this way onto the surface of the
spring element.
3.2.2.1 Strain gage wiring
In order to reduce undesirable influences on the measurement, the strain gages in model 8524 tension
and compression load cells are connected as a Wheatstone bridge. Figure 3 illustrates this wiring in a
simplified form.
Figure 3: Full-bridge strain gage for model 8524 tension and compression load cells
In addition to the four strain gages shown here, compensation resistors to reduce the effect of
temperature and balancing resistors to balance the bridge circuit are also incorporated.
Depending on the version of the model 8524 tension and compression load cell, further resistors for the
purpose of standardizing the full-scale output are integrated into the cable or the connector.
The output voltage U
a
of the model 8524 tension and compression load cell is calculated as follows:
U
a
= c * U
b
• U
b
: Reference excitation voltage
• c: Rated output of the sensor
You can find the rated output “c” on the test certificate for the model 8524 tension and compression load
cell. It is typically in the region of 1.5 mV/V ±0.25%.
In conjunction with the reference excitation voltage (U
b
), in a range of max. 10 V (we recommend 5 V),
signals (U
a
) of around 7.5 mV are produced at 100% loading of the sensor.
3.2.2.2 Full-scale deflection
On sensors that have an elastic membrane, the load depresses the measuring element in the center of
the sensor. This deformation is known as the full-scale deflection, and is so small that it cannot be seen
with the naked eye.
On model 8524 tension and compression load cells, the deformation at maximum load is in the region of
approx. 80 µm and is directly proportional to the load.
3.2.2.3 External forces
External forces here refers to any force that acts outside the sensor’s axis of symmetry – particularly
transverse forces, bending moments and torsional forces.
NOTICE
Damage to the model 8524 tension and compression load cell
Avoid vibrations, even if the generated loads remain below the rated load, and avoid
external forces acting on the load cell. Design your measuring system in such a way as
to prevent these external forces.
IMPORTANT: External forces acting on the model 8524 tension and compression load cell will
significantly falsify the measurement result!